"""Evaluate all variants (correct + mutants) of one problem against all test suites.

Kill criterion follows KernelBench eval: runtime error, shape mismatch, or
!torch.allclose(ref, out, atol=1e-2, rtol=1e-2)  => killed.

Writes JSONL journal (one line per variant x suite). Resumable: already-journaled
(variant, suite) pairs are skipped; a START line without a matching RESULT line
(previous process died there) is recorded as killed:process_crash, and all
remaining suites of that variant are skipped.

Usage: python3 eval_kernel.py <problem> <journal_path>
"""
import importlib.util
import json
import os
import sys

import torch

import kernels_def as K

ATOL = RTOL = 1e-2


def load_ref_model(problem):
    p = K.PROBLEMS[problem]
    spec = importlib.util.spec_from_file_location(f"kb_{problem}", p["kb_file"])
    mod = importlib.util.module_from_spec(spec)
    spec.loader.exec_module(mod)
    init = mod.get_init_inputs()
    return mod.Model(*init), init


def build_ext(problem, variant_id, cuda_src):
    from torch.utils.cpp_extension import load_inline
    p = K.PROBLEMS[problem]
    return load_inline(
        name=f"{problem}_{variant_id}",
        cpp_sources=p["cpp"],
        cuda_sources=cuda_src,
        functions=[p["func"]],
        verbose=False,
    )


def compare(ref, out):
    if not isinstance(out, torch.Tensor):
        return dict(status="killed", reason="not_a_tensor")
    if out.shape != ref.shape:
        return dict(status="killed", reason="shape_mismatch",
                    detail=f"{tuple(out.shape)} vs {tuple(ref.shape)}")
    ok = torch.allclose(ref, out, atol=ATOL, rtol=RTOL)
    if ok:
        return dict(status="survived")
    diff = (ref - out).abs()
    finite = torch.isfinite(out).all().item()
    return dict(status="killed", reason="value_mismatch",
                max_diff=float(diff.nan_to_num(nan=float("inf")).max()),
                out_finite=bool(finite))


def main():
    problem, journal_path = sys.argv[1], sys.argv[2]
    p = K.PROBLEMS[problem]

    done = {}        # (variant, suite) -> True
    crashed = set()  # variants that crashed a previous process
    pending_start = None
    if os.path.exists(journal_path):
        for line in open(journal_path):
            rec = json.loads(line)
            if rec["type"] == "START":
                pending_start = (rec["variant"], rec["suite"])
            elif rec["type"] == "RESULT":
                done[(rec["variant"], rec["suite"])] = True
                pending_start = None

    journal = open(journal_path, "a")

    def emit(rec):
        journal.write(json.dumps(rec) + "\n")
        journal.flush()
        os.fsync(journal.fileno())

    # a START without RESULT means the previous process died on that (variant, suite)
    if pending_start is not None:
        v, s = pending_start
        emit(dict(type="RESULT", variant=v, suite=s, trial=-1,
                  status="killed", reason="process_crash"))
        done[(v, s)] = True
        crashed.add(v)

    ref_model, _ = load_ref_model(problem)
    ref_model = ref_model.cuda().eval()
    suites = p["suites"]()

    # cache reference outputs on CPU: (suite, trial) -> ref_out
    ref_cache = {}

    def ref_out_for(suite_name, builder, trial):
        key = (suite_name, trial)
        if key not in ref_cache:
            inputs = builder(trial)
            with torch.no_grad():
                gpu_in = [t.cuda() for t in inputs]
                ref_cache[key] = ref_model(*gpu_in).cpu()
                del gpu_in
                torch.cuda.empty_cache()
        return ref_cache[key]

    for variant_id, cuda_src in K.all_variants(problem):
        if variant_id in crashed:
            for suite_name, _, _ in suites:
                if (variant_id, suite_name) not in done:
                    emit(dict(type="RESULT", variant=variant_id, suite=suite_name, trial=-1,
                              status="skipped_after_crash"))
            continue

        try:
            ext = build_ext(problem, variant_id, cuda_src)
        except Exception as e:
            for suite_name, _, _ in suites:
                if (variant_id, suite_name) not in done:
                    emit(dict(type="RESULT", variant=variant_id, suite=suite_name, trial=-1,
                              status="killed", reason="compile_error", detail=str(e)[:300]))
            continue

        wrapper_cls = p["wrapper"]
        if problem == "sum":
            model_new = wrapper_cls(ext, 1)
        else:
            model_new = wrapper_cls(ext)
        model_new = model_new.cuda().eval()

        variant_dead = False
        for suite_name, n_trials, builder in suites:
            if (variant_id, suite_name) in done:
                continue
            if variant_dead:
                emit(dict(type="RESULT", variant=variant_id, suite=suite_name, trial=-1,
                          status="skipped_after_crash"))
                continue
            emit(dict(type="START", variant=variant_id, suite=suite_name))
            result = dict(status="survived")
            for trial in range(n_trials):
                ref_out = ref_out_for(suite_name, builder, trial)
                inputs = builder(trial)
                try:
                    with torch.no_grad():
                        gpu_in = [t.cuda() for t in inputs]
                        out = model_new(*gpu_in)
                        torch.cuda.synchronize()
                        r = compare(ref_out.cuda(), out)
                        del gpu_in, out
                        torch.cuda.empty_cache()
                except RuntimeError as e:
                    r = dict(status="killed", reason="runtime_error", detail=str(e)[:300])
                    if "CUDA" in str(e) or "cuda" in str(e):
                        # context may be poisoned; record and let the driver restart us
                        r["trial"] = trial
                        emit(dict(type="RESULT", variant=variant_id, suite=suite_name, **r))
                        journal.close()
                        sys.exit(3)
                if r["status"] == "killed":
                    r["trial"] = trial
                    result = r
                    break
            if "trial" not in result:
                result["trial"] = n_trials
            emit(dict(type="RESULT", variant=variant_id, suite=suite_name, **result))

    emit(dict(type="DONE", problem=problem))
    journal.close()


if __name__ == "__main__":
    main()